The movement has already brought about some changes to Florida gun laws
Young people across the United States have walked out of classrooms to demand tighter gun safety laws, after 17 people were killed in a Florida school shooting last month.
The #ENOUGH demonstrations, led by the survivors of the Marjory Stoneman Douglas High School shooting, saw students commemorate those killed on Valentine's Day and take to the streets in protest.
Students at the school filled its football field holding banners and signs.
The grassroots movement comes after survivors of the attack lobbied politicians in the aftermath of the shooting.
Some met with US President Donald Trump to call for further restrictions on gun ownership - a right protected by the US constitution's Second Amendment.
Crowds of students also poured into the streets of New York - with many dressed in orange, representing the gun control movement.
Addressing the response of politicians to the shooting, one placard read: "Thoughts and prayers are not enough."
Stoneman Douglas student David Hogg told MSNBC: "If our elected officials don't take responsibility for their inaction on both sides of the aisle, then we are going to kick them out of office."
Max Poteat, a student organiser in North Carolina spoke of the emotional walkout.
He said: "I think halfway through it really hit me, and I think everyone around, that these are teenagers just like us and that their lives were taken innocently and that time is needed for change."
Snapchat's stories map showed video posts by students across America and displayed the scale of the walkout.
The movement has already brought about some changes to gun laws in Florida. Last week, the minimum age to purchase rifles was raised from 18 to 21.
However, an outright ban on the type of semiautomatic rifle used in the mass shooting was rejected by politicians.
Plans to strengthen background checks for gun sales seem to be diminishing in Washington.
A large crowd of students chanted slogans in protest outside the White House gates - despite President Trump being in California.
The mass walkout's organisers said students from more than 2,800 schools and groups were taking part in the action, many with the support of their school districts.
The American Civil Liberties Union (ACLU) has backed the demonstrations along with Viacom Inc, which said all seven of its television networks - including MTV - would suspend programming for the 17-minute walkout.
It comes a day after prosecutors said they would seek the death penalty for Nikolas Cruz, who has been charged with 17 counts of premeditated murder and 17 counts of attempted murder.